CN87103360A - Method and device with improved flame passes ejecting gun of adjustable radial and tangential plasma gas stream ratio - Google Patents

Abstract

That plasma torch has is hollow, columnar anode nozzle member and the cylindrical shape cathod elements of arranged coaxial therein.Two member actings in conjunction form the inner passage for the gas that forms plasma.In the rifle body, passage one end comprises the ring-type inlet chamber that is adjacent to negative electrode.Passage advances along the gas stream direction, is defined as annular space between negative electrode and anode member, then continues to arrive the rifle external body by the anode nozzle member.The gas that forms plasma tangentially and is radially introduced inlet chamber by import separately.Provide optionally and to regulate radially and the device of the tangential gas flow of introducing separately can determine air whirl degree by rifle.

Description

Method and device with improved flame passes ejecting gun of adjustable radial and tangential plasma gas stream ratio

The present invention relates to a kind of plasma torch device with and application method.Raise the efficiency by the control that improves plasma gas stream.

Plasma torch can be used in the purposes as thermojet especially.Thermojet relates to for example thermal softening of hot fusible material such as metal or pottery, and softener material is propelled the substrate surface of wanting coated with the shape of particle.Hot particle bumps against and just is bonded to the there on this surface.The heat of the routine as plasma torch is penetrated rifle, not only has been used for heating but also be used for propelling particles.In the plasma spraying rifle, hot fusible material is supplied with this rifle with powdery, typically is made up of small-particle, and the Unite States Standard sieve slot size that for example is lower than 100 mesh counts per square inch is to about 5 microns.

In typical plasma apparatus, electric arc results between the negative electrode of water cooling jet pipe (anode) and neighbor configuration.A kind of inert gas of selecting for use is flowed through between two electrodes and by being ionized behind the electric arc and heating, with regard to the plasma of formation temperature up to 15,000 ℃.Electric arc has been elongated in motion at interelectrode gas effectively, makes more energy pass to electric arc.Plasma by ionized gas is at least in part formed penetrates the similar oxy arc of lighting from jet pipe.

A kind of plasma " flame " ejecting gun of the universal class relevant with the present invention is described in and awarded that private tutor people's such as (W.A.Siebein) the patent No. is 3,145,287 on August 18th, 1964, in the United States Patent (USP) of " flame passes generator and ejecting gun " by name.Such newer rifle structure is 646 in sequence number, in 734 the U.S. Patent application announcement is arranged, this application draws Theo people such as (Anthony F.Dellassio) to propose on September 4th, 1984 by Di, the patent name of application is " nozzle component that the plasma spraying rifle is used ", has transferred and the same assignee of present invention.Present invention can be used as in private tutor's patent or Di draws the change of the structure that is disclosed in the application of Theo to carry out.

During this time, be to be understood that " radially " and " tangentially " is relative terms, as used herein, " tangentially " not only comprises strict slipstream, and comprises string stream, promptly has the stream that significant tangential component is arranged.And, these terms of use and plasma flow path and/or limit the structure example of flow path such as the axis of hole or conduit relevant.

Plasma torch can come work as main plasma gas with argon or with nitrogen traditionally.For argon, this gas is with near the chamber the tangential component introducing negative electrode, so that give plasma with eddy current, this is 3 in for example patent No., 823,302, in the United States Patent (USP) of by name " apparatus and method of plasma spraying " description is arranged, this patent was awarded Mo Er Burger (Muelberger) on July 9th, 1974.The reason of doing like that is not exist under the eddy current situation, electric arc along jet pipe carry (can not sufficiently be elongated) far away inadequately by gas stream, so just can not obtain desired high arc voltage and high efficiency.

On the other hand, at aforesaid United States Patent (USP) 3,145, the radial gas flows input described in 287 generally is to use nitrogen, because it is not easy ionization, because of eddy current tends to electric arc is extended a long distance along jet pipe, can cause electric arc to be difficult to produce.

Yet, as do not have eddy current, concerning nitrogen, arc voltage and efficient are low.Therefore, often for example the such assist gas of hydrogen adds to nitrogen, has the effect of the starting the arc of being easy to, and also allows effective operation even without eddy current.Hydrogen adds in electric arc starting back.Control hydrogen assist gas must cause injection operation complexity and cost greatly, also needs the special measure of pre-blast protection.

Even when eddy current was arranged, the efficient of argon also was desirably not low.May part, hydrogen utilizes once more as additive, and still, this gas usually is considered to not meet the requirements because its inflammability and it can make spraying coating embrittlement.Helium is a kind of substitute, but it is costliness and not too effective.

Usually, it is to make for the gas of the formation plasma of a particular types that every kind of plasma is penetrated rifle, or has radial inlet, or has tangential entry.The rifle of operable any gas typically has different gas distribution rings, and these rings optionally are embedded near the negative electrode, or radial flow is provided, or slipstream is provided; When conversion gas, just need dismounting.Several trials are made, to simplify this conversion.United States Patent (USP) 3,313,908 have disclosed a kind of plasma torch, and it has two types the gas inlet port of using to gas with various, utilizes any in two kinds of extraneous gas pipe joints, can select a ground and select the gas inlet port.This method still needs to change those gun joints, and the adjusting of churning is not provided.

United States Patent (USP) 3,851, No. 140, " on substrate, applying the plasma spraying rifle and the method for coating " by name, award on November 26th, 1974 and to examine mound (Coucher), this patent has shown a kind of plasma spraying rifle with gas distribution ring, and this ring has the main opening that the axis of rifle tilts and the assist openings of radial directed.This two covers INO Intake Open mouth side by side works.It is believed that the variation of this ring control gaseous stream, but do not change ring, will never change gas with various stream; At run duration, also will never change the structural form of gas stream.

Again the U.S. second edition patent Re.25 of the prominent people's such as (A.C.Ducati) that attempts too who publishes on November 21st, 1961 " about increasing the plasma jet bright eruption apparatus and method in base electrode life-span " by name, in 088, the plasma torch that a kind of gas is introduced has been described on two positions that axially separate.Near negative electrode, provide one radially the source as the part of electric arc with the relevant plasma that flows out from the cathodic region by first orifice.In the alveolus that separates in the large diameter downstream of first orifice, provide tangential source of the gas.The air inlet source that these separate does not provide air inlet control in the negative electrode adjacent area, and anode and negative electrode separate widely like that, so that electric arc is difficult to produce.This problem is very serious, thus the generation of electric arc must by moment ground for example the conductor of a slice graphite-like be inserted between the electrode and reach.Structure with kind electrode separates just can't easily produce electric arc by changing admixture of gas or gas stream characteristic.

In view of afore-mentioned, the purpose of existing invention provides a kind of improved plasma spray shooting method and gun apparatus, this device can be single effectively with nitrogen with the operation of eddy current form, its starting the arc of also being not difficult.

Another object of the present invention provides a kind of high efficiency nitrogen flame passes injection method and spray gun device of the easy starting the arc, and in order to improve ignition behavior, it has avoided hydrogen or other gas are added to the needs of nitrogen.

Further purpose of the present invention and advantage from following description and accompanying drawing, are tangible.For example, the present invention allows ejecting gun to use argon, or uses nitrogen, and efficient the best makes the starting the arc easy again.

For realizing the present invention, provide a plasma spraying rifle, it has a columnar cathod elements, and one is coaxial therewith again from its separated hollow cylindrical shape anode nozzle member.The inner passage that the gas of the tangible one-tenth plasma of this plasma torch is used, the one end extends to the outside of rifle.The other end of passage (promptly inner) is initial with the annular inlet chamber that is adjacent to negative electrode, extends towards the direction (being the downstream) of air-flow, enters the space between cathod elements and the anode member, passes through the anode nozzle member therefrom, until body of a gun outside.The plasma spray shooting method comprises the import by separately, radially upcountry reach the gas that tangentially will form plasma and introduce inlet chamber, the amount separately of every kind of gas optionally regulating radially simultaneously and tangentially introduce, decision is by the churning of the gas of this rifle whereby.

Fig. 1 is the end view that embodies plasma spraying rifle structure of the present invention, and part is a profile.

Fig. 2 is the sectional view of gas distribution ring, a part of the plasma spraying rifle of this ring composition diagram 1, it comprises radially and the tangential admission mouth, this figure has schematically described to be attached to the adjuster that separates on the said air inlet, and these adjusters are regulated the gas flow by radially oral instructions are sent with tangential admission discriminably.

Fig. 3 and Fig. 4 are operation curve groups separately, and this curve is represented two kinds of different operational modes of the present invention, make comparisons with the previous operational mode of utilizing nitrogen hydrogen to combine.

Fig. 5 is a kind of radial section of embodiment of distortion of gas distribution ring illustrated in figures 1 and 2.

Referring to accompanying drawing, see Fig. 1 at first especially, this figure part is represented with section, has described to realize a flame spray gun structure of the present invention.This rifle structure is by its integral body of reference number 10 expression, and it can comprise the handle part 12(part of only drawing here).There is a cathod elements 14 inside of rifle, except at one end (towards the gas flow path direction forward), is outside the vertex of a cone; The inner hollow anode nozzle member 16 in addition of rifle, it comprises 1 through hole 17, and the profile of its variation and sectional dimension are coaxial with cathod elements.

As shown in the figure, jet pipe component hole 17 has separately outwards tapered end parts 18 and 20, and a columnar mid portion 22.Awl end section 20 is that flame passes is sent the place, and in the forward end or the outer end that after this will be called hole 17, funnel shaped part 18 then is called the inner.The axial length of the interior wimble fraction 18 in hole 17 extends jointly with the awl end 15 of cathod elements 14 in fact.Tapering on the member 14 usually with the tapering complementation mutually of the inner 18 in hole 17, but the former diameter is more less, and is received therein coaxially, has so just formed an annular space 19, the inner and outer diameter size of this annular space reduces along gas stream direction (forward direction).

In the rifle structure, be enclosed in the zero draft part of negative electrode 14 coaxially, and a radial distance arranged with it, it is a gas distribution ring 28, it is made by electrical insulating material, as the insulation of negative electrode 14 and anode 16, and forms an annular inlet chamber 24, the inner (larger diameter end) of the contiguous annular space 19 in this chamber also has air-flow to communicate with it, thereby for having formed an inner passage by hole 17 to the gas of the formation plasma of the jet pipe outer end of jet pipe member 16.

Gas is by air inlet (26 is one of them), and through ring 28 feeding chambers 24, ring 28 and chamber 24 form gas distributing device together again.

Below link Fig. 2, be described more completely.The gas of the formation plasma of introducing by gas distribution ring 28 will be through at least one radially orifice and at least one tangential orifice.(only representing to have a radially orifice 26 among Fig. 1).

Schematically Biao Shi direct-current arc generator 32 is connected between negative electrode 14 and the anode 16 by on-off switch 34.On-off switch 37 is in parallel with current feedback circuit 32 with high frequency, the high-voltage starter 35 of routine, and this has expression similarly in the drawings.When switch 34 closures, a direct current current potential puts between negative electrode 14 and the anode 16; Then,, starter 35 output superpositions are got on instantaneously, flow through the formation of the ionisation of gas activated plasma of annular space 19 when switch 37 closures.

Shown in figure number 30, in the mouth of anode nozzle 16, provide powder and inject jet pipe, introduce the coated particle flux that one gas carries so that be from the plasma that anode nozzle 16 sends.The plasma that penetrates from anode nozzle 16 absorbs the coated particle that gas carries, fusing or softening they, the surface that their guiding are wanted coated.

Because produce by electric arc at the basic heat of plasma torch inside, so the inside of plasma torch must be cooled off; This reaches with the circulation of cooling fluids such as for example water through the inner passage of rifle usually.Because the arrangement of this internal cooling channel is unwanted to understanding the present invention, do not describe so add among the figure.Yet, be to be understood that these passages must provide.The passage that is suitable for is in relevant patent, and for example aforesaid U.S. Patent 3,145,287 and aforesaid U.S. Patent application numbers 646,734 in diagram is all arranged.

Fig. 2 is the sectional view by gas distribution ring 28, has represented that (26,26A) (36,36A), they allow the gas that forms plasma enter in the chamber 24 that surrounds negative electrode 14 to the radial air inlet orifice with the tangential admission orifice; Although single radial air inlet mouth and single tangential admission mouth a plurality of air inlets of every type are preferably arranged, thereby in Fig. 2, two air inlets of every type have drawn for realizing that the present invention is enough.According to present invention, radially must be able to control respectively with tangential admission mouth gas stream.Schematically represented to reach the air supply system of this requirement in Fig. 2, this system comprises radial gas streamline 38 and 40, and they are by coming out from source of the gas 44, and the gas that flows through radial air flow adjuster 42 provides.Similarly, gas streamline 46 and 48 is received two tangential gas inlets 36 and 36A together, from the gas that provides of source of the gas 44 outflows and process tangential gas flow adjuster 50.Certainly, be same if offer the gas of two different systems, source of the gas 44 and 52 can merge.

Radial air flow adjuster 42 can be equipped with manual adjustment, represents by adjusting knob 54 on symbol.Similarly, tangential gas flow adjuster 50 can be equipped with manual adjustment control, represents by adjusting knob 56 on the symbol.

Air damper 42 and 50 can be by automatic system controller 62, by on figure 58 with 60 pointed being connected, automatically control.Thereby, available manual adjustment, or by automatic system control, gas stream separately can be adjusted with respect to another, reaches the ratio of control slipstream to axial flow, and control gas ratio by rifle according to churning.When if slipstream increases with respect to radial flow, churning just increases thereupon.

For the constant injection of the plasma " flame " that comes out from the rifle jet pipe is provided, require to keep a fixing gas overall ratio often.Thereby, when slipstream changes the ratio of radial flow, usually to reach and keep same total stream by increasing a kind of air-flow and reducing another kind of air-flow.Utilize automatic system controller 62 can realize this requirement.

One of the most useful mode of the present invention's utilization is to obtain the combination of the easy starting the arc and high operational efficiency.When nitrogen with being that this purpose is particularly useful when forming plasma gas.Nitrogen is desired as the gas that forms plasma, because it is inertia on chemical property, inevitable safety because nitrogen, utilizes its molecular separation and the characteristic of combination again as a kind of diatomic gas, has and transmits hot potentiality especially.Yet, have been found that in the presence of strong air whirl, be difficult to the starting the arc with nitrogen.This difficulty of the starting the arc is to be accompanied by the result that eddy current increases the arc path effective length significantly.Yet, in case after the starting, in order to obtain the higher efficient of the energy delivery from electric arc to gas, thereby offer the bigger heating of gas, increase the effective length of arc path by the eddy current that causes increase, be desired.

Like this, one of the most useful mode of the present invention's utilization is only to begin this process with radial flow, triggers electric arc, then introduces slipstream; After this, increase tangential flow component, preferably reduce the radial flow component pro rata,, during this period, increase the energy that is delivered to gas from electric arc so that keep a constant substantially total stream.When nitrogen was used as the gas that forms plasma, this operational mode was particularly useful.

Significantly, the present invention allows to use nitrogen to produce electric arc separately, and the generation of electric arc is easy, has realized the mode of highly effectively moving continuously from hot viewpoint simultaneously.Compare with the common device with nitrogen, it has expressed significant advantage and economy, in common device, in order to help the starting the arc and to reach high efficiency operation characteristic simultaneously, must use for example such gaseous additives of hydrogen.

In device described above, when the electric arc starting the arc, as only using radial flow, then the power from the electric arc supply gas is quite low.Yet along with the increase of tangential component, concentrated vortex is by electrode (14,16) passage between (19), and the gas flow 22,20 of the jet pipe of flowing through, little by little increase arc length, increase voltage thus, and increase the energy that forms the gas of plasma from electric arc.Therefore, passing to the quantity of power of electric arc, by regulating tangential introducing gas and the ratio of radially introducing gas, is adjustable.

Radially the adjustment of tangential gas stream ratio has also been determined the physical location of the electric arc in the rifle jet pipe, i.e. the mean place of the inner surface of electric arc percussion anode nozzle 16.For example, the footpath is found, if slipstream increases enough greatly, just might force the whole length of electric arc extendible nozzle passage 17, and the outer face of percussion anode nozzle member 16 or coupled.This end face is in the outside air, and this result is harmful to this end face, is nonconforming therefore.Yet this is to be used for explanation meeting what's going on when electric arc is elongated.By changing the ratio of slipstream, can select different arc lengths, by optionally changing the electric arc terminal location, scattered the wearing and tearing of electric arc on jet pipe thus, the life-span of jet pipe can be increased.

Although a major advantage of the present invention is to allow to do effectively operation with the plasma torch of for example such pure gas of nitrogen, when radially and tangentially introducing air-flow,, also can use the present invention effectively as with different gas.For example, might use nitrogen, only, then behind the electric arc starting the arc, add for example such assist gas of hydrogen with slipstream radially to introduce as main gas.The hydrogen additive increases by the obtained energy of electric arc, and the slipstream that causes eddy current also can increase by the given energy of electric arc by the rifle passage, so that these two factors act on synergistically, raises the efficiency by adding long arc.Introducing gas separately from the source of the gas that separates is depicted in Fig. 2.

Fig. 3 and Fig. 4 are two sets of curves, are depicted in the operation result in two kinds of different running method of the present invention, and the operational mode that combines with previous use nitrogen hydrogen compares.Fig. 3 illustrates how arc voltage changes, and Fig. 4 illustrates how the heat efficiency changes under different service conditionss.

Earlier referring to Fig. 3, lowest curve 64 is depicted and is being added hydrogen with nitrogen in as the gas stream that forms plasma but during without any eddy current, working voltage is as the situation of change of the function of hydrogen addition.Used per hour 75 cubic feet constant nitrogen current, the hydrogen of adding changes according to nethermost abscissa scale.Like this, when the hydrogen amount from zero when per hour 15 cubic feet (15CFH) changes, total recruitment of its working voltage is about from 60 volts to 70 volts.

By contrast, when curve 66 expression was only used nitrogen, how working voltage increased with the increase of eddy current.One per hour the total flow of 75 cubic feet (75CFH) remain unchanged, and tangential gas stream and thereby the ratio of the eddy current that produces increase.The slipstream gas flow rate is represented by the scale on abscissa top in Fig. 3.Like this, do not increase the gas stream of total formation plasma, higher in fact arc voltage just can reach, shown in curve 66, this is to be sent to the relative gas flow that inlet chamber 24 goes by adjusting simply with slipstream, so that provide the eddy components of an increase to reach in the gas stream of combination.

When the same experiment of being described by curve 66 is a mist with the nitrogen of per hour 75 cubic feet (75 CFH) and the hydrogen of per hour 15 cubic feet (15 CFH) when repeating to do, just obtain results of property by curve 68 expressions.Like this, as can be seen, eddy current and interpolation hydrogen all are effective for increasing arc voltage.

Arc voltage normally and pass to the heat efficiency of rifle of energy aspect of the gas that forms plasma from electric arc closely-related, and promptly high voltage has been indicated high efficiency usually.Yet, offer the electrical power of electric arc and just might measure BTHE by deducting because of row gives the power loss amount (temperature is appreciated and be multiply by flow velocity) of the rifle that the heat of cooling water causes by measurement.This difference has represented to pass to the actual power of plasma, and the validity on the coating process.The heat efficiency is the ratio of this difference to power source.Because of the curve 64A in 4,66A, 68A have described the front respectively with reference to the heat efficiency of 64,66, the 68 described every group of service conditionss of the curve among Fig. 3.In Fig. 4, expression has the abscissa scale identical with Fig. 3.

Even it is very interesting and be to exist the efficient of the purity nitrogen air-flow test that eddy current described by curve 66A to want high a lot of significantly compared with the efficient of the nitrogen hydrogen combination of being described by curve 64A.And although the voltage characteristic between the curve 66 and 68 separates quite greatly among Fig. 3, the heat efficiency of these two kinds of operational modes does not have big difference, and as can be seen, the interval of curve 66A and 68A is very approaching.

Though all examples of above special discussion all relate to nitrogen, perhaps the combination of nitrogen and hydrogen is appreciated that, for other gas of the such formation plasma of argon for example, perhaps other form the various combinations of the gas of plasma, and the present invention also is very useful.For example,, as main gas nitrogen as assist gas, also is fine with argon.

Such as in distributing ring 28A among accompanying drawing Fig. 5 the signal face of land shows, the radially head piece of some or all, for example 26B, 26C, can in their sagittal plane, tilt, so that they and electrode 14,16 axle acutangulates, and the radial inner end of head piece is positioned at the place ahead of its radial outer end like this, so just form axial component forward of air-flow of the gas of plasma.

In the above description, having meant so-called " tangentially " stream is very clearly to have done qualification and identifiable, and it and radial flow are entirely different.Yet, should be appreciated that not at any gas stream of absolute radial direction, can consider to have a tangential component.Thereby, do not break away from spirit of the present invention, can provide an airflow inlet to the tangential admission mouth with meeting the requirements, it does not provide maximum tangential effect to entering gas, and this can dress up certain angle with air inlet wittingly and reach between the position that the pure position of radially importing can be provided and can provide maximum tangentially to import.On the other hand, in fact " radially " air inlet has a little tangential component, and " tangentially " air inlet then has big tangential component.

Another useful feature of the present invention is to change can doing simple the variation promptly between the slipstream of one of the radial flow of one of percentage hundred and percentage hundred aspect the control.Radial flow is generally used nitrogen, and slipstream is generally used argon.Like this, this device can fade to another kind of gas from a kind of gas soon.

Although this invention has been got in touch specific most preferred embodiment and illustrated and describe, those skilled in the art can expect various changes and modification in this technology.Thereby following claim is used for limiting the effective range of the present invention for prior art, and comprises all changes and the modification that belongs to true spirit of the present invention and effective range.

Claims (14)

1, a kind of method of using plasma torch to produce plasma, this rifle has a hollow cylindrical shape anode nozzle member and a cylindrical shape cathod elements, these two component coaxial ground configurations and separated from one another, so that limit the inner passage for the gas that forms plasma, this passage has an end that extends to this rifle outside, the inner that forms by a ring-type inlet chamber that is adjacent to negative electrode, and extend interlude between negative electrode and the anode member, said method comprises:

Radially inwardly introduce in the inlet chamber gas that forms plasma, and the gas that will form plasma is introduced inlet chamber in the mode with tangential component, optionally regulate radially simultaneously and the ratio of the tangential gas of introducing, set up and determine churning thus by the gas of this rifle.

2, according to a kind of method of claim 1, wherein said radially and the introducing of tangential gas be simultaneous.

3, according to a kind of method of claim 1, wherein gas is only radially introduced when initial, then applies the voltage starting the arc between negative electrode and anode member, tangentially introduces gas then to set up the eddy current by the gas of this rifle.

4, according to a kind of method of claim 3, the gas that wherein forms plasma is made up of nitrogen in essence.

5, according to a kind of method of claim 1, the additional step that comprises is tangentially introduced gas to radially introducing the ratio of gas for voltage being applied between negative electrode and the anode member in order to the starting the arc and adjustment, and control passes to the quantity of power of electric arc whereby.

6, according to a kind of method of claim 1, the additional step that comprises is for after setting up at gas stream, voltage is applied between negative electrode and the anode member in order to the starting the arc, adjust the tangential gas of introducing then to radially introducing the ratio of gas, be controlled at arc length or arc physics position in the rifle jet pipe thus.

7, a kind of method as claimed in claim 1 wherein has the gas with various of different ionization properties, radially and tangentially introduces separately.

8, the method for claim 1 further comprises radially and tangential gas stream is made inverse variation and kept total gas stream constant.

9, a kind of device that comprises the generation plasma of plasma torch comprises:

A rifle body, this rifle body has hollow columnar anode nozzle member and is configured in wherein also separated columnar cathod elements, so that in rifle, form the passage that the gas stream of plasma is used, and extend to the outside of rifle, said negative electrode and the acting in conjunction of anode nozzle member, make and in said passage, produce the electric arc that forms plasma, the inner of said passage is that the ring-type inlet chamber by the adjacent cathodes member forms, and extends between negative electrode that separates and anode member and by said anode nozzle member; Be configured in the said plasma spraying gun in order to the gas that will form plasma and introduce gas distributing device in the said inlet chamber, this gas distributing device comprises at least one radial air inlet hole and at least one tangential admission hole, this hole extends into and ends in the said inlet chamber, by radially interacting to produce the air whirl by said gas passage with the gas of tangential formation plasma of said air admission hole separately; Adjusting device separately, be used for control flows cross said radially with the gas flow in tangential admission hole; And adjust the device of said adjusting device with respect to another, in order to the eddy current of the gas of control by said gas passage ratio to axial flow.

10, according to a kind of device of claim 9, wherein said gas distributing device comprises a plurality of radial air inlets hole and a plurality of tangential admissions hole, and these air admission holes are opened along the peripheral intervals of said inlet chamber.

11, according to a kind of device of claim 9, wherein the substantial portion in the space between said negative electrode and anode nozzle member is an annular, and the substantial axial overlap of a said cylindrical shape anode nozzle member and said cathod elements is wherein arranged.

12, according to a device of claim 11, wherein said annular has a little radial dimension so that impel electric arc therebetween to burst out.

13, according to a device of claim 12, comprise that the coated particle that gas is carried is incorporated into the device in the plasma flow, this plasma stream flows downstream from said jet pipe member ejaculation with from said cathod elements.

14, the plasma device of claim 9, the central axis of said negative electrode is radially upcountry aimed in wherein said radial air inlet hole basically, but with the public plane of said axis in have to tilt so that an axial motion component forward is provided for said gas.

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